Warning and stopping device for knitting machines



Sept. 5, 1939. CLMITSCHELE 2 WARNING AND STOPPING DEVICE FOR KNITTING MACHINES Fifed Dec. 27, 1938 2 Sheets-Sheet l 2 C. MITSCHELE Sept. 5, 1939.

WARNING AND STOPPING DEVICE FOR KNITTING MACHINES Filed Dec. 27; 1938 2 Sheets-Sheet 2 Patented Sept. 5, I939 UNITED STATES WARNING AND STOPPING DEVICE F KNITTING MACHINES Carl Mits chele, Pforzheim, Germany Application December 27, 1938, Serial No. 247,955 In Germany August 27, 1936 Claims.

The invention relates .to a warning or stopping device for knitting machines which is influenced by irregularities in the runningpf the thread or yarn, such as the passage of a knot or slub,

5 breakage of the yarn or the like, the yarn passing between two guides which are arranged close behind one another and at least one 0i which is pivotally mounted and acts upon the warning or stopping device. In hand operated machines, warning is generally effected by means of signals and in motor driven machines -it is efiected inechanically or electrically by automatic stopping of the machine.

The purpose of such devices is above all to give immediate warning of small or large knots of any size, and even thickened portions of yarn in order to prevent defects in. the fabric and trouble in the machine. At thehigh running speed the yarn does not support any load owing to the danger of breakage.

In order to ensure immediate and satisfactory warning of knots and the like, it is necessary to enclose the yarn on all sides at a guiding place so closely that warning may be given even of thickened portions of yarn. On the other hand,

the passage of the knot should not produce excessive yarn tension, so that the knot will be signalled but can escape without hindrance.

' In the devices known heretofore, the narrowing of the yarn passage orifice for adaptation to the thickness of the yarn or to the size of the knots was effected at the expense of excessive yarn tension, the danger of breakage being, however, considerably increased. I Other devices possess pivotal guides but with a calibrated passage for the yarn. Such devices, however, are unreliable in operation because large knots result in breakage of the yarn, while small knots pass through without any warning being efiected. It is clear that such devices which, in addition to pivoting,

also have to exert some contact pressure, increase still further the loading of the yarn.

For obviating the above-mentioned disadvantages, the device according to the invention is so constructed that in known manner the first guide is stationary and the second is pivotal and the outwardly pivotal guide; which is at the boundary of unstable equilibrium and is open at one side, and the stationary'guide are adjustable relatively to one another in accordance with the [thickness of the yarn, and in the position of readiness form a common passage orifice which encloses the yarn on all sides and which, upon a knot or the like impinging on the pivotal bear-' .ing is very rapidly increased in size due to'a 'tionary guide, the yarn being bent and thereby without one-sided stressing of the yarn tension.-

slight outward pivoting or said bearing, and consequently ceases to enclose the yarn and allows the knot to escape without hindrance at the open side of the pivotal guide. Inthis construction of the invention, during 5 the passage of a yarn knot or thickened portion, the latter owing to the guides being positioned one below the other, first impinges on the stapressed under the movable guide. In an im 10 proved construction-of the invention, the arrangement is such that the yarn knot or thickened portion is engaged simultaneously by both guides so that it can escape without bending and This also dispenses with enclosure of the yarn on all sides.

This construction is characterized in that two outwardly pivotal guides in unstable equilibrium are situated adjacent one another in the position 20 of readiness and with their adjacent open ends enclose the yarn on all sides or partly, in accordance with its thickness, and upon the occurrence of a knot or thickened portion of yarn, simultaneously pivot outwardly in known man- 25 ner, independently of the form of the knot. In this case, both an audible and visual signal is operated thereby dispensing with the tedious search for the source of the fault.

Two constructions of a. device according to the invention are shown diagrammatically'by way of example in theaccompanying drawings wherein:

Figures Ito 4 show one construction, Figure 1 being the basic position of the device and Figure 3 2 the altered position of the device after the arrival of a knot. Figure 3 the position in the case of exhaustion, of the yarn or yarn breakages, seen from the side and Figure 4 the. yarn passage seen from above on a larger scale. 40

Figures 5 to 7 show the second construction, Figure 5 showing the device in the p 'ition of readiness, Figure. 6 a part of the device in perspective and Figure '7 the device after the arrival of a knot. 45

The yarn a, which for example has a knot in and a thickened portion 112 is first guided by a guide opening in provided on the stationary frame b. In this guide opening, the yarn a, a1, a: can only yield inwardly, that is to say towards the right in Figure 1, but not on the contrary outwardly, that is to say to the left in Figure 1. From this guide, the yarn is introduced into a groove d1 recessed in the end of a tilting lever (I mounted at d: on the support 0. Unlike the operation of the guide in, in this case the yarn cannot yield inwardly but only outwardly. In the basic position of the tilting lever d (see Figure 1), therefore, the yarn a is entirely enclosed by the two guides but in such a manner that the yarn has a slight play in the guide In and groove (11 so that no friction is set up against the yarn. If now the knot a1 comes within the region of the guide b1, the place of the knot is bent in the guide hr by half the amount of the increase between the normal yarn thickness and the thick ness of the knot, the knot or the thickened portion of yarn pressing very efiectively under the groove d1. To enable the knot or thickened portion a: to escape from the guide b1 and groove d1 again, the tilting lever d has first to make. at its arm having the groove d1 an upwardly yielding pivotal movement (see Figure 2). This is carried out so that the knot of or az can escape conveniently without producing any considerable yarn tension, and at the same time, in consequence of the downward movement of the end of lever arm d which has the claw do, the claw d3 releases a drop lever e, the latter owing to its slight excess weight swinging out on its pivot er and striking a bell f, or in the case for example of power machines, automatically stopping the machine electrically. It is important that the centre of gravity of the tilting lever d is arranged on the same side as the groove d1 fairly close to its pivot dz so that there is almost unstable equilibrium. By means of the set screw is, the support 0 may be moved forward and with it the drop lever 6, thus exactly adjusting the passage orifice for the yarn a to any yarn thickness.

Warning or stoppage of a motor-driven machine is likewise efiected by the drop lever e also in the case of yarn breakages or exhaustion of the spools, as is shown in Figure 3.

After leaving the passage orifice for knots and thickened portions of yarn, theyarn a is first guided by a stationary yarn guide ba, mounted ona frame rail b2. Located above this stationary guide is a yarn feeler lever g pivoted on the pin yi- If the yarn breaks between the machine and the yarn tensioning device not shown in the drawings, the yarn is no longer drawn taut and bends in consequence of the oblique position of the yarn feeler lever g which then swings on the are 92. An intermediate lever 12., one lever arm of which rests on the yarn feeler lever g, also drops with the yarn feeler lever, its right-hand lever arm hr moving upwardly and pressing the lever arm ii of a further lever 11, i1 upwardly and the other lever 'arm 2' thereof downwardly, the latter pressing on the wire support 114 and releasing the claw d: which supports the drop lever e. The end of the yarn a is also signalled in the same way (see Figurefi), but with the difference that in this case the yarn is drawn entirely out of the elements b2, g. In this case also, however, the yarn as bends even before, once only a small amount of yarnis left. In order to prevent any pressure or hard contact on the guided yarn, the levers g, h and i, ii are made of light wire. As with the exception of the drop levers h andg, the other levers i, ii and d which have an influence on the yarn a. are in almost unstable equilibrium, the yarn a passes through the yarn testing places practically without any additional tension.

In the construction according to Figures 5, 6 and '7, the yarn a with its knots a1 and thickened portions a2 passes through the orifice ll of the stationary support in the frame 1, and between the two outwardly pivotal guides m, m. In the position of readiness, the two guides enclose the yarn either completely or only partly. Their ends may therefore be of difierent constructions. They either possess each a semicircular or arcuate opening, both openings when joined together forming a yam passage of circular oval or other shape, ora slit-shaped opening formed by rod.- like or bridge-like guide ends. In both cases, adjustment in accordance with the yarn thickness may be made either on both or only on one yarn guide. The adjustment is shown particularly clearly in Figure 6, where the sheath-like guide m1 slides over the rail-shaped end of the tilting lever 11 and is fixed by a wing nut n.

If a knot a1 enters the passage orifice, it engages the two guides simultaneously at least at two opposite points, whereby the two guides, which are in unstable equilibrium, cease to enclose the yarn even in the event of a slight impact and tilt upwardly and outwardly in a brief but wide angle of swing, the yarn being simultaneously released without bending or danger of breakage being possible. The drop lever e is released by the downward movement of the lever arm with the claw (is situated on the other side of the pivot (is. drop lever e over the disc e2 now swinging out on the other side of the pivot, the said drop lever strikes the bell f. The, disc 12 which is of particularly recognisable appearance and is fixed to the framel by'means of the bracket laus'nmultaneously rendered visible. In the case of motordriven machines where automatic electrically operated stoppage is provided in place of the signal by bell, this identification disc is of particular significance, as generally a large number of knot signalling devices, for example twenty or more, are employed on one machine. The source of the trouble may thus be ascertained with certainty.

To prevent thickened portions of yarn or knots which are situated only on one side of the yarn from lifting the guide m alone, there is situated at one or both ends of the transverse member of the latter, a catch or dog 0 which, upon the outward movement ensures the simultaneous release of the guide mi. The other parts of the device do not difier from the construction accord-.

ing to Figures 1 to 4 and have been provided with the same references.

Warning of yarn breakages and spool exhaustion and stoppage of the machine in the case of motor drive is effected in the manner already described in connection with the first construction.

I claim:

1. A warning or stopping device for knitting machines which is influenced by irregularities in the running of the yarn, such as the passage of knots, breakage of the yarn or the like, wherein the yarn passes through two guides arranged close behind one another, at least one of which is pivotally mounted and acts upon the warning or stopping device, characterised in that the first guide is stationary and the second is pivotal, and that the outwardly pivotal guide, which is situated at the boundary of unstable equilibrium and is open at one side, and the stationary guide are adjustable relatively to one another in accordance with the yarn thickness and in the position of readiness form a common passage orifice which encloses the yarn on all sides and which, upon a knot or the like impinging on the pivotal guide is very rapidlyincreased in size, consequently Owing to the excess weight of the ceases to enclose the yarn and allows the knot to escape without hindrance at "the open side of the pivotal guide.

2. A device as claimed in claim 1, characterised in that a yarn feeler lever operative in the event of yarn breakageand exhaustion of the spool upon its release acts through intermediate levers on the pivotal guide.

3. A device as claimed in claim 1, characterised in that two outwardly pivotal guides situated in unstable equilibrium are adjacent in the position of readiness and between their adjacent open sides provide a passage for the yarn appropriate to its thickness, and on the arrival of a knot or thickened portion of yarn swing outwardly simultaneously in known manner, independently of the form of the knot.

4. A device as claimed in claim 1, characterised by the provision of an identification disc and means for exposing it simultaneously with the actuation of a bell signal.

5. A device as claimed in claim 1, characterised by the provision of an identification disc and means for exposing it simultaneously with the actuation of means, for automatically stopping the machine.

' CARL MITSCHELE. 

